Commit Graph

2 Commits

Author SHA1 Message Date
Jeff Epler
9632360caa
Use a macro to compute the size of arrays at compile time (#18044)
* Add ARRAY_SIZE and CEILING utility macros

* Apply a coccinelle patch to use ARRAY_SIZE

* fix up some straggling items

* Fix 'make test:secure'

* Enhance ARRAY_SIZE macro to reject acting on pointers

The previous definition would not produce a diagnostic for
```
int *p;
size_t num_elem = ARRAY_SIZE(p)
```
but the new one will.

* explicitly get definition of ARRAY_SIZE

* Convert to ARRAY_SIZE when const is involved

The following spatch finds additional instances where the array is
const and the division is by the size of the type, not the size of
the first element:
```
@ rule5a using "empty.iso" @
type T;
const T[] E;
@@

- (sizeof(E)/sizeof(T))
+ ARRAY_SIZE(E)

@ rule6a using "empty.iso" @
type T;
const T[] E;
@@

- sizeof(E)/sizeof(T)
+ ARRAY_SIZE(E)
```

* New instances of ARRAY_SIZE added since initial spatch run

* Use `ARRAY_SIZE` in docs (found by grep)

* Manually use ARRAY_SIZE

hs_set is expected to be the same size as uint16_t, though it's made
of two 8-bit integers

* Just like char, sizeof(uint8_t) is guaranteed to be 1

This is at least true on any plausible system where qmk is actually used.

Per my understanding it's universally true, assuming that uint8_t exists:
https://stackoverflow.com/questions/48655310/can-i-assume-that-sizeofuint8-t-1

* Run qmk-format on core C files touched in this branch

Co-authored-by: Stefan Kerkmann <karlk90@pm.me>
2022-08-30 10:20:04 +02:00
Stefan Kerkmann
3f5dc47296
[Core] Use polled waiting on ChibiOS platforms that support it (#17607)
* Use polled waiting on platforms that support it

Due to context switching overhead waiting a very short amount of time on
a sleeping thread is often not accurate and in fact not usable for timing
critical usage i.e. in a driver. Thus we use polled waiting for ranges
in the us range on platforms that support it instead. The fallback is
the thread sleeping mechanism.

This includes:

* ARM platforms with CYCCNT register (ARMv7, ARMv8) this is
  incremented at CPU clock frequency
* GD32VF103 RISC-V port with CSR_MCYCLE register this is incremented at
  CPU clock frequency
* RP2040 ARMv6 port which uses the integrated timer peripheral which is
  incremented with a fixed 1MHz frequency

* Use wait_us() instead of chSysPolledDelayX

...as it is powered by busy waiting now.

* Add chibios waiting methods test bench
2022-07-11 15:17:05 +02:00